1. Technical Field
Embodiments described herein generally relate to processors. In particular, embodiments described herein generally relate to processors having on-die memories to store data.
2. Background Information
Logarithmic, exponential, cosine, sine, hyperbolic sine, arc-tangent, reciprocal square root, and various other transcendental math functions are commonly evaluated in processors. For example, such transcendental math functions are often used in scientific applications, physics-based computational graphics, and other applications where such functions appear.
In order to evaluate certain more common transcendental math functions, some processors include an on-die read only memory (ROM) that stores a hardware lookup table that has approximate or starting values for the transcendental function. The hardware lookup table is typically programmed into the on-die ROM by the processor's manufacturer at the time when the processor is manufactured. During use, when the function needs to be evaluated (e.g., by a software application), an appropriate value may be retrieved from the hardware lookup table. Commonly, the values stored in the table may be those fixed values that the processor's manufacturer believes are the most generally useful and/or useful for the most common applications. In some cases, the retrieved value may have an accuracy and/or precision sufficient for the intended use. In other cases, when higher accuracy and/or precision values are desired, the retrieved value may be iteratively refined in software.